Thanks for all of your suggestions, and I apologize for the bad screenshot.
I've investigated and my mesh is set to 5m, the AES file is second from the bottom of the Scenery Library just above the two defaults, and my insertion points seem ok (thanks for the link! I've set the insertion points before but I didn't really understand what I was doing.)
I went back to KSEA to redo the screenshot, and something strange has happened. The issue used to be a giant cliff directly in front of the plane on runway 34R, but it now looks completely different (screenshot attached, I hope...). Not correct, just different. I swear that I didn't change a single setting in FSX. I did take a short flight from Juneau to Gustavus yesterday just to check to see if Southern Alaska was ok (and it is - the elevation issues seem to be confined to PNW, yet it looks just the same as the other regions in the Scenery Library).
If you know of anything else I can check I would appreciate your suggestions. If not, I can try the Orbx forum, but I wanted to ask here first because people at RTMM are very knowledgeable, experienced, and friendly. I really can't wait to get RTMM reinstalled.